Could cancer be our oldest ancestor?

Before the Cambrian flowering of multicellular life, there was a period of about a billion years where cells began to get together and form rudimentary colonies, says Davies, director of the BEYOND Center for Fundamental Concepts in Science at ASU and principal investigator of a major research program funded by the National Cancer Institute, who is one of two scientists proposing a theory that suggests cancer cells are living fossils.

"These rudimentary colonies, I think, were like the earliest tumors. So when people get cancer now, these tumors represent a throwback to that time about a billion years ago – that first experimentation with multicellularity," Davies says.